In the context of producing plastic bottles, it is customary that preforms are placed in a blow mould and are expanded in this blow mould for example by means of compressed air. Furthermore, in order to expand these preforms, usually a stretching rod is provided which carries out a stretching of the preform during the expansion process. In the prior art, such a stretching rod was in the past used for stretching different plastic containers. More recently, however, attention is increasingly being paid during the production of plastic containers to saving materials and obtaining uniform distributions of the material of the plastic bottle. The stretching rods, which are usually arranged on a support, are therefore also often changed when expanding different containers.
EP 1 694 492 B1 discloses an arrangement for releasably fixing a stretching rod on a slide. In said document, the stretching rod has on its outer circumference a precisely defined outer profile, and a housing has a mating profile adapted to this outer profile. In order to insert the stretching rod, the stretching rod is rotated into a position in which it can be passed through a top face of the housing. The stretching rod is then rotated inside the container and can in this way no longer be displaced in its longitudinal direction. An arresting of the stretching rod is thus possible as a result of this rotation of the stretching rod with respect to the housing. This apparatus offers a rapid possibility for changing stretching rods. However, in order to change the stretching rods, it is necessary for these to be rotated with respect to the housing. This is often problematic due to the accessibility of the stretching rod. Moreover, in the case of EP 1 694 492 B1, a rotation of the stretching rod with respect to the housing in the operating state must be prevented by additional releasable arresting means.
It may therefore be desirable to allow an uncomplicated and rapid process for changing stretching rods, wherein at the same time a high stability of the stretching rod with respect to its mount is achieved during working operation.